1. Field of the Invention
It is known that air can, in principle, be transported with the aid of a so-called electric ion-wind or corona-wind. An electric ion-wind is created when a corona electrode and a target electrode are placed at a distance from one another and each connected to a respective terminal of a d.c. voltage source, the corona electrode and the d.c. voltage source being such as to cause a corona discharge at the corona electrode. This corona discharge results in ionization of the air, with the air ions having the same polarity as the polarity of the corona electrode, and possibly also in the production of electrically charged aerosols, i.e. air-suspended solid particles or liquid droplets which are electrically charged as a result of collisions with the electrically charged air ions. The air ions move rapidly from the corona electrode to the target electrode, under the influence of the electric field, where they relinquish their electric charge and return to electrically neutral air molecules. During their movement from the corona electrode to the target electrode, the air ions are in constant collision with the electrically neutral air molecules, therewith transferring electrostatic forces to the neutral air molecules, so as to draw these molecules from the corona electrode to the target electrode, resulting in the transportation of air in the form of a so-called ion wind or corona wind.
2. Description of the Related Art
Earlier proposed arrangements for transporting air with the aid of ion-wind are found described, for example, in DE-OS-2854716, DE-OS-2538959, GB-A-2112582, EP-A1-29421, U.S. Pat. No. 3,374,941 and U.S. Pat. No. 4,380,720. These prior art arrangements have been found extremely ineffective, however, and have not achieved any significance in practice. Air transporting arrangements which utilize the ion-wind principle and which display marked improvements over the aforesaid known arrangements, both with regard to efficiency and to practical utility, are described in our international patent application PCT/SE85/00538.